Drug & supplement interaction

Skullcap + Phentermine

Phentermine brand names: Adipex-P, Fastin, T Diet, Phentride, Obenix, and others.

No Known Interaction

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Updated July 2026 · Pair last verified Sep 20, 2026

The bottom line No known interaction

We found no known interaction between Skullcap and Phentermine in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first.

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Interaction report

Skullcap and Phentermine

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Phentermine and Skullcap in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Skullcap safety at a glance

Skullcap overall Use caution Often used short-term, but evidence is limited and product quality varies, so use with care.

Pregnancy Avoid Not enough safety data, so it is best avoided during pregnancy.

Breastfeeding Avoid Safety is unknown, so avoid while breastfeeding.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Phentermine and Skullcap? Ask Dr. Brian Staiger, PharmD, BCPS directly ›

How we checked

Why No Interaction Is Listed for Phentermine

Interactions in our licensed database are recorded against drug classes, not just single drug names. Phentermine is filed under 2 classifications — stimulant drugs, oral drugs. Skullcap has documented interactions with 1 drug class — the most serious being cns depressants (moderate) — and none of Phentermine’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Skullcap Does Interact With Other Medications

Skullcap has 248 moderate known drug interactions in our database — Phentermine isn’t one of them. If you take anything else, check it against the full list below.

Moderate 248 No known interaction 2,582 (incl. Phentermine)

Taking anything else?

Check Another of Your Medications Against Skullcap

Covers the 2,830 medications we’ve checked against Skullcap. Pick one to open its full report.

What to actually watch for

What Skullcap Itself Has Been Linked To

This is not an interaction — nothing below involves Phentermine. It is the side-effect record for Skullcap on its own, from the licensed Natural Medicines monograph. If something new turns up after you add Skullcap, this list is the first place to look. One entry is worth acting on rather than waiting out — marked below.

Memory problems Worth acting on Additional detail
“A single skullcap extract dose of 100 mg does not seem to have adverse CNS effects. However, a higher dose of 200 mg might cause sedation and cognitive impairment. One patient taking skullcap 350 mg three times daily for 2 weeks reported vivid dreams. It is unclear if this event was associated with skullcap.”

Skullcap · Natural Medicines adverse-effect record, reported in cognitive impairment.
2 sources cited

12216. Wolfson P, Hoffmann DL. An investigation into the efficacy of Scutellaria lateriflora in healthy volunteers. Altern Ther Health Med 2003;9:74-8.

91690. Brock C, Whitehouse J, Tewfik I, Towell T. American skullcap (Scutellaria lateriflora): a randomised, double-blind placebo-controlled crossover study of its effects on mood in healthy volunteers. Phytother Res 2014;28(5):692-8.
Vivid dreams or nightmares Additional detail

Recorded for Skullcap in the same Natural Medicines adverse-effect record shown under Memory problems above.
Drowsiness Additional detail

Recorded for Skullcap in the same Natural Medicines adverse-effect record shown under Memory problems above.

Everything above comes from the Natural Medicines adverse-effect record for Skullcap — expand a row for the licensed statement it rests on. We read the ADVERSE REACTIONS section of Phentermine’s FDA label too, and the two lists don’t meaningfully overlap — which is why no Phentermine column appears here.

Overlapping uses

What Phentermine Is Prescribed For, and What Skullcap Has Been Studied For

These two come up together because they touch the same health topic — not because they do the same job. Phentermine is a prescription medicine with approved uses on its FDA label. Skullcap is a supplement: what follows is what researchers have looked at it for, and how strong that evidence is.

Phentermine is prescribed for: Phentermine is approved as a short-term addition to a weight-loss program — not a standalone treatment. It is used alongside reduced-calorie eating, increased physical activity, and behavior changes to help manage obesity in adults whose body mass index (BMI) is 30 kg/m² or higher, or 27 kg/m² or higher when other risk factors such as controlled high blood pressure, diabetes, or high cholesterol (hyperlipidemia) are also present. All available phentermine products — including Adipex-P, Lomaira, and various generic capsules and tablets — share this same FDA-approved use. Lomaira tablets are specifically dosed to be taken three times daily before meals, while other formulations are generally taken once daily.

Read the rest of what Phentermine is prescribed for

Treatment is intended to last only a few weeks.

Skullcap has been studied for:

Hyperlipidemia studied, not established Skullcap has been studied for this. Natural Medicines rates the evidence: Insufficient Reliable Evidence To Rate Read what the research shows

Skullcap for hyperlipidemia

Although there has been interest in using oral skullcap for hyperlipidemia, there is insufficient reliable information about the clinical effects of skullcap for this purpose.

Effectiveness ratings and the research summaries above are the verbatim record from the Natural Medicines database, which grades evidence from “Effective” down to “Insufficient Reliable Evidence To Rate”. A rating below the top of that scale means researchers have looked at it — not that it works, and never that it can stand in for a prescribed medicine. Do not stop or replace Phentermine on your own; if you are taking Skullcap for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.

From our Q&A

Questions About Skullcap or Phentermine

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Skullcap or Phentermine, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Phentermine

This page covers Skullcap only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Phentermine page lists 61 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Ephedra (major), Peyote (major), Rauvolfia Vomitoria (major) and Sida Cordifolia (major).

By severity: 5 major · 43 moderate · 13 minor.

From our pharmacist’s overview on the Phentermine page

“Ephedra is the pairing I most want anyone taking phentermine (Adipex-P) to know about. Phentermine is itself a stimulant appetite suppressant that raises heart rate and blood pressure, and ephedra piles the same cardiovascular strain on top of it.”

Reviewed by 2 · Jul 18, 2026

Open the Phentermine interaction page

One more smart check

Taking Skullcap as Part of a Dietary Supplement Product? Check It for Interactions

We hold 926 real supplement products containing Skullcap, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Skullcap. Even though Skullcap itself has no known interaction with Phentermine, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Skullcap and Phentermine Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Skullcap

Top 25%

#199 of 1,452 supplements looked up here in the last 7 days

29 days ago today

Medication Phentermine

Top 25%

#663 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Where does our data come from?

Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Skullcap reference on this page ↓
Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Skullcap and Phentermine records this page draws on were last updated July 10, 2026.
What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.

Data structure & sourcing designed and verified by Dr. Brian Staiger, PharmD, BCPS.

Supplement

About Skullcap

What is Skullcap?

Anxiety and stress
Trouble sleeping
Nervous tension
Muscle spasms
General relaxation

American skullcap is an herb traditionally used to calm anxiety and promote relaxation, but solid human evidence is very limited. It is generally considered relatively safe for short-term use in healthy adults, though it should be avoided in pregnancy and breastfeeding and used cautiously because of possible liver concerns and product mislabeling.

Scutellaria lateriflora · Lamiaceae · Above-ground parts (leaves, stems, and flowers) · Tea, capsules, tinctures, liquid extracts, dried herb

An interaction check asks whether these two react with each other — it does not ask whether Skullcap is a good idea for someone in your situation. Here is what our Skullcap record says about it on its own.

Skullcap: dosing

There is no official, standardized dose for American skullcap. The right amount can vary depending on the product and the form (tea, capsule, or tincture).The safest approach is to follow the directions on the product label and not take more than recommended.

From our Skullcap monograph — the full record covers uses, side effects and every documented interaction.

Read the full Skullcap monograph & all interactions

Medication

About Phentermine

What Is Phentermine Used For?

Brand names: Adipex-P, Fastin, T Diet, Phentride, Obenix, Pbc Phentride, Pbw Phentride, Phentrol #3, Ionamin, Phentrol #6, Phentrol #2, Phentrol #5, Phentrol, Obermine, Phentermine, Suprenza

Phentermine is approved as a short-term addition to a weight-loss program — not a standalone treatment. It is used alongside reduced-calorie eating, increased physical activity, and behavior changes to help manage obesity in adults whose body mass index (BMI) is 30 kg/m² or higher, or 27 kg/m² or higher when other risk factors such as controlled high blood pressure, diabetes, or high cholesterol (hyperlipidemia) are also present.

All available phentermine products — including Adipex-P, Lomaira, and various generic capsules and tablets — share this same FDA-approved use. Lomaira tablets are specifically dosed to be taken three times daily before meals, while other formulations are generally taken once daily. Treatment is intended to last only a few weeks.

See full Phentermine drug information

Keep checking

Other Drugs & Skullcap

Browse every other medication we’ve checked against Skullcap — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major

248Moderate

0Minor

2,581No known interaction

248 Moderate 2,581 No interaction

Moderate

248 interactions

Showing 60 of 248 moderate interactions — see all 248 on the Skullcap page.

No interaction 2,581 drugs checked — show the list

We also checked Skullcap against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,581 medications checked with no known interaction — see the full Skullcap list.

See the full Skullcap interactions page

See every supplement checked against Phentermine, ranked by severity

Evidence & sources

Skullcap References

The 3 references that drive our Skullcap monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

Wolfson P, Hoffmann DL. An investigation into the efficacy of Scutellaria lateriflora in healthy volunteers. Altern Ther Health Med 2003;9:74-8.
Awad, R., Arnason, J. T., Trudeau, V., Bergeron, C., Budzinski, J. W., Foster, B. C., and Merali, Z. Phytochemical and biological analysis of skullcap (Scutellaria lateriflora L.): a medicinal plant with anxiolytic properties. Phytomedicine. 2003;10(8):6 PubMed
Brock C, Whitehouse J, Tewfik I, Towell T. American skullcap (Scutellaria lateriflora): a randomised, double-blind placebo-controlled crossover study of its effects on mood in healthy volunteers. Phytother Res 2014;28(5):692-8.

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Skullcap and Phentermine Together: Common Questions

Is it safe to take Skullcap with Phentermine?

We do not list a known interaction between Skullcap and Phentermine. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.

Are Skullcap and Phentermine used for the same thing?

They overlap in purpose, which usually means the real question is whether you need both rather than whether they are safe together. This page lists the shared uses and how strong the evidence is for Skullcap in each. That is a conversation for your prescriber, especially if Phentermine is being adjusted to a target.

How was the Skullcap and Phentermine combination checked?

Interactions in our licensed database are recorded against drug classes. Phentermine is filed under 2 classifications, and Skullcap has documented interactions with 1 drug class — none of Phentermine's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.

Does Skullcap interact with any other medications?

Yes. Skullcap has 248 documented drug interactions in our database — Phentermine is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.

Does Phentermine interact with any supplements?

Yes. Phentermine has documented interactions with 61 supplements in our database — Skullcap is not one of them. The Phentermine interaction page linked on this page lists every one, ranked by severity.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Where next

Keep Exploring

Skullcap monograph Uses, safety profile, and every drug interaction in one place Phentermine drug information The full plain-English guide to this medication Phentermine supplement interactions Every supplement checked against Phentermine, ranked by severity Supplement interaction checker Check any supplement or product against your medications Browse medications A–Z Every drug we’ve checked against herbs & supplements References The 3 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Phentermine and Skullcap?

Our pharmacists answer your medication & supplement questions — free.

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.