Drug & supplement interaction

Deer Velvet + Ulipristal Acetate

Ulipristal Acetate brand name: Ella.

Minor Interaction
Medically reviewed by · Updated September 2026
The bottom line Minor

Deer Velvet has a minor interaction with Ulipristal Acetate. Theoretically, deer velvet might interfere with the effectiveness of contraceptive drugs.

Read the full interaction report
SeverityMinor
LikelihoodUnlikely
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Deer Velvet and Ulipristal Acetate

Here is the interaction we found between these two, with the evidence behind it.

Minor

CONTRACEPTIVE DRUGS

Why this applies to Ulipristal Acetate

Ulipristal Acetate falls under CONTRACEPTIVE DRUGS — the group Deer Velvet interacts with.

Theoretically, deer velvet might interfere with the effectiveness of contraceptive drugs.
Laboratory research shows that deer velvet contains small quantities of estradiol and testosterone. While clinical research shows that taking deer velvet extract does not raise testosterone levels, estradiol levels were not measured.
Severity Minor Likelihood Unlikely Evidence D

Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans..

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the short version: this is a theoretical concern, not something proven in people. The worry is that deer velvet contains tiny amounts of natural hormones, including estradiol, and extra estrogen activity could in theory work against how ulipristal (Ella) does its job. Ulipristal prevents pregnancy mainly by delaying the release of an egg, so anything that nudges your hormones could, on paper, make it a little less reliable.

In real life, the amounts of estradiol in deer velvet are very small, and we have no human studies showing a problem. Since Ella is a one-time emergency contraceptive, my honest advice is to give it the best chance to work. If you've recently used deer velvet, just mention it to your pharmacist or doctor so they can weigh in.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Sleivert, G., Burke, V., Palmer, C., Walmsley, A., Gerrard, D., Haines, S., and Littlejohn, R. The effects of deer antler velvet extract or powder supplementation on aerobic power, erythropoiesis, and muscular strength and endurance characteristics. Int PubMed
  2. Bubenik, G. A., Miller, K. V., Lister, A. L., Osborn, D. A., Bartos, L., and van der Kraak, G. J. Testosterone and estradiol concentrations in serum, velvet skin, and growing antler bone of male white-tailed deer. J Exp Zoolog.A Comp Exp Biol 3-1-2005;30 PubMed

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Deer Velvet Also Interacts With Other Medications

Deer Velvet has 51 minor known drug interactions in our database — the Ulipristal Acetate one above is one of them. If you take anything else, check it against the full list below.

Minor 51 No known interaction 2,779 (incl. Ulipristal Acetate)
Taking anything else?

Check Another of Your Medications Against Deer Velvet

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

Everything else you take

See Every Supplement That Interacts With Ulipristal Acetate

This page covers Deer Velvet only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Ulipristal Acetate page lists 158 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Grapefruit (major), St. John's Wort (major), Acacia Rigidula (moderate) and Adrafinil (moderate).

By severity: 3 major · 107 moderate · 48 minor.

From our pharmacist’s overview on the Ulipristal Acetate page

“St. John's wort worries me most with ulipristal acetate (Ella), the emergency contraceptive that gets exactly one chance to work.”

Reviewed by 2 · Jul 18, 2026

Open the Ulipristal Acetate interaction page

One more smart check

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

We hold 249 real supplement products containing Deer Velvet, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Deer Velvet. Your product may carry other ingredients that interact with Ulipristal Acetate too, on top of Deer Velvet — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Deer Velvet and Ulipristal Acetate 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 Deer Velvet
Top half

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

29 days ago today
Medication Ulipristal Acetate
Steady interest

#2,332 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.

Supplement

About Deer Velvet

What is Deer Velvet?

Deer Velvet
  • Athletic performance and strength
  • Energy and fatigue
  • Joint health and arthritis
  • Immune support
  • Sexual function and libido

Deer velvet is a traditional remedy made from the soft, growing antlers of deer or elk, and it is most often promoted for energy, athletic performance, and joint health. Good-quality human evidence is limited, and most claims are not well proven. Talk to your pharmacist or doctor before using it, and avoid it during pregnancy and breastfeeding.

Read the full Deer Velvet monograph & all interactions
Medication

About Ulipristal

What Is Ulipristal Used For?

Brand name: Ella

Ella (ulipristal acetate) is used to prevent pregnancy after unprotected sex or when another form of birth control has failed or was used incorrectly. It must be taken as soon as possible, within 5 days (120 hours) of that event.

Ella is intended for occasional, emergency use only — it is not a substitute for regular, ongoing contraception.

See full Ulipristal drug information
Keep checking

Other Drugs & Deer Velvet

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

0Major
0Moderate
51Minor
2,778No known interaction
51 Minor 2,778 No interaction
Minor

51 interactions

No interaction 2,778 drugs checked — show the list

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

Showing the 60 most looked-up of 2,778 medications checked with no known interaction — see the full Deer Velvet list.

See the full Deer Velvet interactions page
See every supplement checked against Ulipristal Acetate, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Deer Velvet monograph › Uses, safety, and every drug interaction in one place Ulipristal Acetate supplement interactions › Every supplement checked against Ulipristal Acetate, ranked by severity Ulipristal drug information › The full plain-English guide to this medication Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Deer Velvet and Ulipristal Acetate Together: Common Questions

Can you take Deer Velvet with Ulipristal Acetate?
There is only a minor interaction, which is usually not serious. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Deer Velvet and Ulipristal Acetate interaction?
We rate it Minor. This interaction is generally not clinically significant, but it remains worth noting and discussing with your pharmacist.

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

Still Have a Question About Ulipristal Acetate and Deer Velvet?

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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.