Drug & supplement interaction

Hcg Diet + Clemastine

Clemastine brand name: Tavist Allergy.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between Hcg Diet and Clemastine 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. Additionally, although there is no interaction, the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Hcg Diet and Clemastine

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 Clemastine and Hcg Diet in our sources. This does not guarantee that the combination is completely free of risk — research on Hcg Diet alongside specific medications may be limited.

Worth understanding: our licensed dataset holds no drug-interaction record for Hcg Diet at all — not against Clemastine, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.

Hcg Diet is an eating pattern rather than something you take. Ask your pharmacist or doctor before changing how you eat while on a prescribed medicine: some medicines are dosed around meals, and a change in diet can change how they work. 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.

Hcg Diet safety at a glance

Hcg Diet overall Avoid hCG is not proven for weight loss and the very low-calorie diet it requires can be harmful.
Pregnancy Likely Unsafe When used by injection. HCG, which is a component of the HCG diet, is teratogenic. It has been linked to a high rate of congenital abnormalities in animal model... Read the full pregnancy detail
Breastfeeding Avoid Very low-calorie diets and added hormones are not safe while breastfeeding.

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Clemastine and Hcg Diet? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

No Interaction Found — But Data Suggests Hcg Diet and Clemastine May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so following Hcg Diet while taking the medicine can make those effects more likely to turn up, and harder to pin on one or the other if they do.

  • Mood changes or irritability / Anxiety or restlessness / Tiredness / Headache Additional detail

    Hcg Diet

    “The HCG diet can cause headache, fatigue, irritability, restlessness, and depression.”

    Hcg Diet · Natural Medicines adverse-effect record, reported in cluster headache.

    2 sources cited
    1. 17042. Novarel (Chorionic Gonadotropin) prescribing information. Steris Laboratories, March 2006.
    2. 17301. Birmingham CL, Smith KC. Human chorionic gonadotropin is of no value in the management of obesity. Can Med Assoc J 1983;128:1156-7.

    Clemastine

    Listed in the ADVERSE REACTIONS section of the FDA label for Clemastine. Read the label on DailyMed ›

  • Nausea Additional detail

    Hcg Diet

    “The HCG diet can cause refeeding syndrome. In one case report, a patient developed refeeding syndrome, including severe muscle weakness, nausea, hypophosphatemia, hypokalemia, elevated creatine kinase, and ST-segment depression with marked U waves, after taking HCG 1000 IU subcutaneous daily and restricting food consumption to less than 500 calories per day for 3 weeks.”

    Hcg Diet · Natural Medicines adverse-effect record, reported in depression.

    1 source cited
    1. 109513. Schunemann MJ, Bertschinger M, Trachsel C, Bachli E. Severe refeeding syndrome after human chorionic gonadotropin diet: a potentially lethal complication. BMJ Case Rep 2021;14(11):e244011. PubMed

    Clemastine

    Listed in the ADVERSE REACTIONS section of the FDA label for Clemastine. Read the label on DailyMed ›

Reported for Hcg Diet but not commonly for Clemastine: blood clots, muscle weakness, breast tenderness and low potassium.

Effects for Clemastine come from the ADVERSE REACTIONS section of its FDA label; effects for Hcg Diet come from the Natural Medicines adverse-effect record, quoted above. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Special populations

Hcg Diet in Pregnancy & Breastfeeding

Pregnancy Likely Unsafe

When used by injection. HCG, which is a component of the HCG diet, is teratogenic. It has been linked to a high rate of congenital abnormalities in animal models. Do not use HCG or follow the HCG diet while pregnant.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

From our Q&A

Questions About Hcg Diet or Clemastine

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Hcg Diet or Clemastine, 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 Clemastine

This page covers Hcg Diet only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Clemastine page lists 72 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Henbane (major), Scopolia (major), Alfalfa (moderate) and Angel's Trumpet (moderate).

By severity: 3 major · 57 moderate · 12 minor.

From our pharmacist’s overview on the Clemastine page

“Clemastine (Tavist Allergy) is an older, sedating antihistamine that already dries the mouth, blurs vision, and slows the gut, and that is exactly why this list earns real caution rather than a quick skim. Thirty of the 72 supplements on file pile the same drying, sedating anticholinergic load on top, and two of the three major-rated e…”

Reviewed by 2 · Jul 18, 2026

Open the Clemastine interaction page

How much people look this up

Where Hcg Diet and Clemastine 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 Hcg Diet
Steady interest

#1,226 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Clemastine
Steady interest

#1,827 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 Hcg Diet reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Hcg Diet and Clemastine records this page draws on were last updated July 11, 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 .
Eating pattern

About Hcg Diet

What is Hcg Diet?

  • Rapid weight loss
  • Appetite control during dieting
  • Body fat reduction

The HCG diet pairs a very low-calorie diet (often around 500 calories a day) with human chorionic gonadotropin, a pregnancy hormone, and claims to cause fast, targeted fat loss. There is no good scientific evidence that hCG helps with weight loss or hunger, and the FDA has not approved it for this use; any weight lost comes from the extreme calorie restriction, which can be dangerous. Talk to your doctor or pharmacist before trying any HCG product.

Human chorionic gonadotropin (hCG) hormone, used with a very low-calorie diet · Injections, sublingual (under-the-tongue) drops, oral pellets, sprays

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

Hcg Diet: dosing

There is no safe or approved dose of hCG for weight loss. Because the FDA has not approved this use, no reliable dosing exists, and over-the-counter products are not standardized or proven.We do not recommend the HCG diet. Never start a very low-calorie diet or use hormone products on your own.

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

Read the full Hcg Diet monograph & all interactions
Medication

About Clemastine

What Is Clemastine Used For?

Brand name: Tavist Allergy

Clemastine treats symptoms of allergic rhinitis (hay fever and similar nasal allergies) — including sneezing, runny nose, itching, and watery eyes. The oral solution (Clemastine Fumarate syrup) is indicated for adults and children aged 6 through 12 years. The tablets (Clemastine Fumarate and Clemsza) are indicated for adults.

Clemastine also treats mild, uncomplicated allergic skin reactions — specifically urticaria (hives) and angioedema (swelling under the skin) — at the appropriate dosage level, in both the oral solution and tablet forms.

See full Clemastine drug information
Keep checking

Other Drugs & Hcg Diet

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

0Major
0Moderate
0Minor
2,829No known interaction
2,829 No interaction
No interaction 2,829 drugs checked — show the list

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

Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full Hcg Diet list.

See the full Hcg Diet interactions page
See every supplement checked against Clemastine, ranked by severity
Evidence & sources

Hcg Diet References

The 4 references that drive our Hcg Diet 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.

  1. Novarel (Chorionic Gonadotropin) prescribing information. Steris Laboratories, March 2006.
  2. Birmingham CL, Smith KC. Human chorionic gonadotropin is of no value in the management of obesity. Can Med Assoc J 1983;128:1156-7.
  3. Goodbar NH, Foushee JA, Eagerton DH, et al. Effect of the human chorionic gonadotropin diet on patient outcomes. Ann Pharmacother. 2013 May;47(5):e23. PubMed
  4. Schunemann MJ, Bertschinger M, Trachsel C, Bachli E. Severe refeeding syndrome after human chorionic gonadotropin diet: a potentially lethal complication. BMJ Case Rep 2021;14(11):e244011. PubMed

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

Following Hcg Diet While Taking Clemastine: Common Questions

Is it safe to follow Hcg Diet while taking Clemastine?
We do not list a known interaction between Hcg Diet and Clemastine. 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.
Do Hcg Diet and Clemastine have any of the same side effects?
Yes — our sources link each of them separately to 5 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
Does Clemastine interact with any supplements?
Yes. Clemastine has documented interactions with 72 supplements in our database — Hcg Diet is not one of them. The Clemastine 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

Hcg Diet monograph Uses, safety profile, and every drug interaction in one place Clemastine drug information The full plain-English guide to this medication Clemastine supplement interactions Every supplement checked against Clemastine, 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 4 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Clemastine and Hcg Diet?

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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.