Horsewood Side Effects: Safety Notes and Drug Interactions
Written by the Horsewood Formula editorial desk
Last updated · Who reviewed this page · How we write and review
Horsewood side effects are best checked ingredient by ingredient, and each one has known cautions.
Saw palmetto may add to bleeding risk, horny goat weed has reports of fast heart rhythm, and tongkat ali has rare liver injury reports. Take no more than two capsules a day, and ask a doctor first if you take any medication.
For who should check first, see who Horsewood is for.
Does Horsewood have side effects?
The side effects of Horsewood itself are unknown, because the finished capsule has never been tested in a published study. What we know comes from research on its seven label ingredients.
The label adds its own warning: "Do not exceed recommended dose. Pregnant or nursing mothers, children under the age of 18 and individuals with a known medical condition should consult a physician before using this or any dietary supplement."
Heart rhythm
Horny goat weed has case reports of fast heart rhythm, mostly in older men with heart disease.
Bleeding
Saw palmetto may add to bleeding risk with blood thinners and around surgery.
Liver and quality
Tongkat ali has rare liver injury reports and uneven product quality.
Horsewood ingredient safety table
Each Horsewood ingredient has its own safety record, and the label prints every amount. The table gives the main caution for each line, with its source.
A small amount does not remove an interaction or an allergy.
| Ingredient | Horsewood amount | Main safety note | Source |
|---|---|---|---|
| Saw palmetto berry | 20 mg | May raise bruising and bleeding risk with blood thinners; heavy bleeding in surgery reported. | (MSKCC, 2023) |
| Horny goat weed | 8 mg (10:1) | Case reports of fast heart rhythm and rash; controlled human trials lacking. | (Drugs.com, 2026) |
| Tongkat ali | 10 mg (100:1) | Rare liver injury reports; long-term safety not well known. | (NIDDK LiverTox, 2024) |
| Tongkat ali products | Not tested here | Some products found with lead, mercury or hidden sildenafil. | (OPSS (DoD), 2023) |
| Nettle leaf | 20 mg | Reviewed by LiverTox; research focused on root, with mixed results. | (NIDDK LiverTox, 2023) |
| Boron chelate | 20 mg compound | Adult limit is 20 mg elemental boron a day from all sources. | (NIH ODS, 2022) |
| Wild yam root | 20 mg | Does not turn into DHEA or other hormones in the body. | (MSKCC, 2022) |
| Sarsaparilla root | 20 mg | Not enough evidence to rate it for any use. | (RxList, n.d.) |
| Capsule and fillers | Not stated | Gelatin (animal-derived), microcrystalline cellulose, magnesium stearate. | Label |
Can Horsewood raise bleeding risk or affect surgery?
It may, because Horsewood contains saw palmetto. Saw palmetto may raise bruising and bleeding risk with blood thinners, and case reports describe heavy bleeding during surgery (MSKCC, 2023).
The Horsewood amount is 20 mg, far below the usual 320 mg (NCCIH, 2025). No study has checked bleeding at this dose.
Ask your doctor before starting if you
- Take a blood thinner or any drug that affects clotting
- Have a bleeding disorder or bruise easily
- Have surgery or dental work planned
Can the horny goat weed in Horsewood affect your heart?
It can in rare cases. Case reports describe fast heart rhythm and rash with horny goat weed, especially in older people with heart disease (Drugs.com, 2026).
Its benefits for sexual function have not been proven in rigorous trials, and human studies are small (NIDDK LiverTox, 2022). Horsewood holds 8 mg of a 10:1 extract, and the label does not state the icariin content.
Why heart health comes first
Erection problems can be an early warning sign of heart disease. In one study, men who developed ED had about a 25% higher risk of later heart and blood vessel events (Thompson et al., 2005).
Men with ED should be checked for heart disease (AUA, 2018), high blood pressure or diabetes (NIDDK, 2024) (MedlinePlus, 2025).
Is the tongkat ali in Horsewood a liver concern?
It is a rare but recorded concern. LiverTox notes that the long-term safety of tongkat ali is not well known, and that product strength and purity are not standardized (NIDDK LiverTox, 2024).
Operation Supplement Safety reports that some tongkat ali products held lead, mercury or hidden sildenafil (OPSS (DoD), 2023). Horsewood has no independent lab report on record.
Liver warning signs: stop and call a doctor
- Yellow skin or yellowing in the whites of the eyes
- Dark urine or new itching after you begin
How much boron is in Horsewood, and can it go too high?
Horsewood lists 20 mg of boron amino acid chelate per serving, but not the elemental boron inside it. Adults should not go above 20 mg of elemental boron a day from all sources (NIH ODS, 2022).
The chelate weight includes the amino acid part, so the elemental boron is lower. The exact figure is not published.
Do wild yam or sarsaparilla in Horsewood act like hormones?
No. The body cannot turn wild yam into DHEA, progesterone or testosterone (MSKCC, 2022) (RxList, n.d.). In older adults, three weeks of wild yam did not change DHEA-S levels (Araghiniknam et al., 1996).
The claim that sarsaparilla turns into anabolic steroids is false (RxList, n.d.). Neither herb is a hormone treatment.
Which medicines need a doctor's check before Horsewood?
Every prescription deserves a check before Horsewood, because supplements can interact with medicines (NIH ODS, 2023). Some drug types have a known concern tied to one ingredient.
| Medicine or situation | Ingredient or risk | Concern |
|---|---|---|
| Blood thinners | Saw palmetto | More bruising or bleeding |
| Planned surgery | Saw palmetto | Bleeding during the procedure |
| Nitrates for chest pain | Hidden-drug risk in this category | Dangerous drop in blood pressure |
| Heart or blood-pressure drugs | Horny goat weed | Heart rhythm and blood pressure effects |
| Prescription ED pills | Horsewood is not a substitute | Ask before combining anything |
| Hormone treatment | Whole formula | Ask your doctor first |
| Multivitamin with boron | Boron chelate | Total boron near the upper limit |
| PSA blood test | Saw palmetto | No PSA change in CAMUS; still tell your doctor |
Read how our medical reviewer checks these safety notes.
What to do if you react to Horsewood
If something feels wrong after taking Horsewood, stop the capsules first. Then match your next step to how serious it is.
- 1
Stop the capsules
Leave out the next dose. Do not push through a reaction.
- 2
Call 911 if severe
Chest pain, fainting, trouble breathing or a swollen face need emergency care.
- 3
Call your doctor
Bring the bottle so your doctor can read the full label.
- 4
Report it to FDA
Use FDA's MedWatch program to report a bad reaction to a supplement.
- 5
Contact the order desk
For a refund, call +1 (641) 711-1414 with your order ID.
Refund steps are on the guarantee page.
Who should not take Horsewood without a doctor's OK?
People under 18 should not take Horsewood. Anyone with a known medical condition should consult a physician first, as the label says.
Horsewood does not treat erectile dysfunction, low testosterone or any prostate condition. Our who it is for page has the full fit check.
- Men on blood thinners, nitrates, or heart or blood-pressure drugs
- Men with heart disease or a heart rhythm problem
- Anyone with past liver trouble
- Anyone avoiding animal products, since the capsule is gelatin
Horsewood side effects: common questions
Common search questions, answered from the label and the sources cited on this page.
Is Horsewood safe?
No safety study of the finished Horsewood capsule exists, so nobody can call it proven safe. Several ingredients carry known cautions, so ask a doctor or pharmacist first if you take any medicine or have a medical condition.
Can Horsewood cause stomach upset?
Stomach effects have not been published for Horsewood, because the capsule has never been studied. Take it with the 8 oz glass of water the label asks for, and stop if an upset stomach keeps coming back.
Can horny goat weed cause a fast heartbeat?
Case reports describe fast heart rhythm and rash with horny goat weed, mostly in older people with heart disease (Drugs.com, 2026). Horsewood lists 8 mg of a 10:1 extract and does not state its icariin content.
Can boron be toxic?
Too much can be harmful, which is why adults have an upper limit of 20 mg of elemental boron a day (NIH ODS, 2022). Horsewood lists 20 mg of boron chelate, a compound weight, so its elemental boron is lower but not stated.
Does saw palmetto affect PSA tests?
In the CAMUS trial, saw palmetto at 320 to 960 mg a day did not change PSA more than placebo (Andriole et al., 2013). Horsewood holds 20 mg. Still tell your doctor about every supplement before a PSA test.
Should I stop Horsewood before surgery?
Tell your surgeon you take it. Saw palmetto may raise bleeding risk, and case reports describe heavy bleeding during surgery (MSKCC, 2023). Your surgical team will tell you when to stop.
Can Horsewood interact with blood pressure medicine?
It might. Horny goat weed may affect heart rhythm and blood pressure, so check with your doctor or pharmacist before combining Horsewood with any heart or blood-pressure drug.
Can tongkat ali harm the liver?
Rare liver injury reports exist for tongkat ali, and its long-term safety is not well known (NIDDK LiverTox, 2024). Stop and call a doctor if you notice yellow skin or eyes, or dark urine.
When should I call a doctor about a supplement reaction?
Stop the supplement and call your doctor for a rash, racing heart, unusual bruising, or yellow skin or eyes. Call 911 for chest pain, fainting, trouble breathing or a swollen face.
