DHT blockers offer the potential to support hair growth and reduce hair loss, but some of them may come with side effects. Take a look at some common DHT blockers and their potential side effects below.
Finasteride is the most widely studied DHT blocker and is one of the only DHT blocker ingredients that is approved by the FDA for hair loss and benign prostatic hyperplasia (BPH). It is administered at 1 mg per day for hair loss and 5 mg per day for BPH.
Despite its FDA approval, finasteride does come with some potential side effects:
In a clinical meta-study1, 1,879 men with male pattern baldness were given either an oral dose of finasteride at 1 mg per day or a placebo. The study found that that about 7.7 percent of those taking finasteride experienced treatment-related adverse effects compared to just 7 percent of those taking the placebo. This represents a 0.7% higher chance of developing side effects while taking DHT blockers for hair loss.
The incidence of sexual function disorders was 1.7% greater in men taking finasteride compared to placebo. 3.8% of the men treated with finasteride versus 2.1% of those taking the placebo developed sexual side effects such as:
0.5% higher chance of decreased libido (1.8% in the finasteride treated group compared to 1.3% in the placebo group)
0.5% higher chance of ejaculation disorders (1.8% in the finasteride treated group compared to 0.6% in the placebo group)
0.6% higher chance of erectile dysfunction (1.3% in the finasteride treated group compared to 0.7% in the placebo group)
These sexual dysfunction symptoms went away after stopping finasteride treatment.
Who should avoid DHT Blockers?
Regardless of the information available on natural DHT blockers, we recommend avoiding them if you are pregnant or breastfeeding. These ingredients work on your hormones and may interact directly with DHT, which plays a role in developing fetuses and infants. They are generally not recommended for teens either.
Natural DHT Blocker Side Effects
Along with finasteride, other natural DHT blocker ingredients may pose their own side effects. Much of the following information was compiled by searching for natural DHT blockers and listing their side effects from reputable sources and published case reports.
May Act as a Blood Thinner
Some case reports have found that saw palmetto may act as a blood thinner. This increases bleeding time as well as the time it takes for wounds to clot. If you have any sort of surgical procedure done, it’s highly recommended to inform your doctor when you are using a supplement containing saw palmetto. Your doctor will usually advise you to stop taking saw palmetto at least one week prior to the surgery.
Low Chance of Sexual Dysfunction
Saw palmetto is generally reported to have lower rates of causing sexual dysfunction disorders compared to finasteride. See our article on how saw palmetto works for hair loss to learn more. Experts suggest that saw palmetto has fewer systemic side effects than prescription DHT blockers because it mainly acts on DHT levels in tissues (like hair follicles and the prostate) rather than in the blood.
Lower Blood Glucose Levels
In a rat study, stinging nettle extract was found to significantly lower blood glucose levels. This may be caused in part by reduced glucose absorption in the intestine. This suggests that stinging nettle extract may cause hypoglycemia, making it a potential concern for those with diabetes.2
Lower Blood Pressure
In another rat study, rats were given a continuous intravenous stinging nettle extract at a low dose of 4 mg per kg per hour, a high dose of 24 mg per kg per hour, or a control diuretic. Compared to the control rats, the rats receiving the stinging nettle extract showed significantly reduced arterial blood pressure, suggesting a direct effect on the cardiovascular system.3
Increased Urine Production
The same study also found that the rats given stinging nettle extract showed increased urine production and an increased excretion of sodium in the urine. This suggests that stinging nettle may also have an effect on the kidneys.3
Pumpkin Seed Oil
Well tolerated, little side effects
Pumpkin seeds are normally eaten with little side effects. Concentrated pumpkin seed oil has been found to be helpful for BPH symptoms and was well tolerated in several studies.7, 8
May Cause Indigestion
Side effects for pygeum extract are believed to be rare. The most commonly reported side effects include nausea and indigestion.
Both human and animal studies involving soy have found that its isoflavones may inhibit thyroid enzymes. Soy and soy products are not recommended for those with hypothyroidism (low thyroid activity).4
Soy also contains phytoestrogens, which are essentially plant-based compounds that mimic natural human estrogen. Due to this phytoestrogenic activity, soy is not recommended for women who have had forms of estrogen receptor-positive breast or endometrial cancers.
Phytoestrogens, consumed in excessive amounts, may also cause problems for men. In one case, a 60-year-old man presented bilateral gynecomastia for a period of six months with no other symptoms. Researchers discovered that the patient’s estrone and estradiol levels were four times the regular levels.
They then discovered that the man had been drinking three quarts of soy milk per day. Things returned to normal after the patient discontinued drinking soy milk.5 This is a rare case and demonstrates that excessive consumption can result in negative effects. Make sure any product you take is consumed is formulated with reasonable and effective doses.
Prescription DHT blockers like finasteride block the production of DHT and help with hair loss in men and women. The incidence of sexual side effects of prescription 1 mg finasteride are only about 1.7% higher in men compared to placebo.
Natural DHT blockers appear to have lower side effects as they block DHT in different ways.