Does Testosterone Cause Acne and Hair Loss?

Testosterone therapy can cause acne. That's a straightforward yes. It's listed as a common side effect in the product literature for licensed UK testosterone preparations including Testogel and Tostran, affecting roughly 1 in 10 to 1 in 100 patients. Hair loss is a more complicated story, and it's one where most people have the wrong idea.

This article covers both, because if you're on testosterone replacement therapy (TRT) or considering it, these are often the first two side effects you'll search for.

Why Testosterone Causes Acne#

Testosterone is an androgenic hormone, meaning it has direct effects on tissues that contain androgen receptors. Sebaceous glands (the oil-producing glands in your skin) are packed with them.

When testosterone levels rise, these glands respond by producing more sebum. Excess sebum mixes with dead skin cells and bacteria inside hair follicles, blocking them and creating the conditions for acne to develop. It's the same mechanism that causes breakouts during puberty, when androgen levels spike naturally.

The process involves a conversion step. An enzyme called 5-alpha reductase converts testosterone into dihydrotestosterone (DHT) inside the skin. DHT is a more potent androgen than testosterone itself, and it binds more aggressively to the receptors in sebaceous glands. DHT also alters the keratinisation process inside follicles, encouraging the formation of comedones (blackheads and whiteheads) before they progress into inflammatory spots.

This is why people with a history of acne during their teens are more prone to flare-ups on TRT. The underlying sensitivity of your sebaceous glands to androgens doesn't disappear with age.

When Does TRT-Related Acne Start?#

Most people who develop acne on testosterone therapy notice it within the first two to six weeks of starting treatment. This coincides with the initial rise in circulating androgen levels as the body adjusts to the new hormonal environment.

For some, it's mild: a few spots on the chest, back, or shoulders. For others, particularly those with a genetic predisposition, it can be more significant and persistent. The face tends to be affected less commonly than the trunk in TRT-related acne, though this varies.

Acne that develops as a direct response to starting testosterone often stabilises after the first three months as hormone levels reach a steady state. If it doesn't improve, or if it's severe from the outset, that's a signal to speak to whoever is prescribing your testosterone.

Managing Acne During Testosterone Treatment#

The good news is that TRT-related acne is manageable, and you generally don't need to stop treatment to get it under control.

First steps (over the counter):

• Benzoyl peroxide wash or gel (available in most UK pharmacies) reduces bacteria on the skin surface and can make a significant difference for mild to moderate acne
• Adapalene 0.1% gel (now available OTC in the UK under the brand Differin) is a retinoid that normalises skin cell turnover and prevents comedone formation
• Regular but gentle cleansing of the affected areas, particularly after exercise

If over-the-counter options aren't enough: Your GP can prescribe topical antibiotics (such as clindamycin), oral antibiotics including tetracyclines, or in stubborn cases, refer you to a dermatologist. NICE guidance on acne management (NG198) provides a clear treatment ladder, and it applies equally to hormone-related acne.

For severe, cystic acne that doesn't respond to first or second-line treatments, isotretinoin (Roaccutane) is an option. It's highly effective but comes with significant considerations including the MHRA's strengthened safety monitoring requirements introduced in recent years. This would only be initiated by a dermatologist, not a GP, and would require careful thought about the ongoing testosterone therapy.

The formulation of testosterone you're using can also matter. Injections (such as Nebido or Sustanon 250) cause sharper peaks and troughs in testosterone levels compared to gels, and some patients report worse skin during the post-injection peak. If acne is a persistent problem, discussing a change in formulation with your prescriber is worth raising.

Does Testosterone Cause Hair Loss?#

Here's where the myth needs correcting: testosterone itself does not cause hair loss. The research is fairly consistent on this point. Studies show no significant link between overall testosterone levels and hair loss from the scalp.

What does cause hair loss is DHT, and that distinction matters.

DHT is produced when 5-alpha reductase converts free testosterone. Around 10% of a man's testosterone is converted to DHT through this pathway. Once DHT is in circulation, it can bind to receptors on scalp hair follicles. In men who are genetically susceptible, this causes those follicles to miniaturise gradually: the hairs become finer, shorter, and lighter until the follicle eventually closes and stops producing hair altogether.

Men with androgenetic alopecia (male pattern baldness) can have more than 50 times the concentration of DHT within their hair follicles compared to men without hair loss. The sheer quantity of DHT at the follicle level, combined with how sensitive those follicles are to its effects (determined by your androgen receptor genes), drives the process.

This is fundamentally a genetic condition. Twin studies estimate that genetics accounts for around 80% of male pattern hair loss risk. Having high testosterone doesn't make it more likely; having genes that make your follicles sensitive to DHT does.

TRT and Hair Loss Risk#

So if DHT is the culprit, and TRT raises testosterone levels, does TRT accelerate hair loss?

The honest answer is: it can, but only in men who were already genetically predisposed. If you have no family history of male pattern baldness and your androgen receptor genes don't make your follicles particularly sensitive to DHT, starting TRT is unlikely to trigger meaningful hair loss.

If you do carry the genetic risk, raising testosterone levels gives the 5-alpha reductase enzyme more substrate to work with. More free testosterone means more potential DHT. In men who were heading towards pattern baldness anyway, TRT can accelerate the timeline rather than cause something entirely new.

Interestingly, very low testosterone is associated with reduced body hair, including armpit, pubic, and facial hair, because male hormones stimulate growth of body and facial hair. Scalp hair follows different rules because the follicles there respond to DHT very differently from follicles elsewhere on the body.

Blocking DHT: What Actually Works#

If you're concerned about hair loss, whether you're on TRT or not, two treatments have solid clinical evidence behind them.

Finasteride works by inhibiting 5-alpha reductase, which reduces DHT production throughout the body by around 70%. Less DHT means less stimulation of the miniaturisation process in genetically susceptible follicles. It doesn't work overnight: most men need three to six months before they notice stabilisation, and up to a year to see meaningful regrowth. The key is starting early, because once a follicle has fully closed, it cannot be reopened.

Minoxidil works differently. It's a vasodilator that improves blood flow and oxygen delivery to hair follicles. It doesn't address DHT directly but supports follicle health and can extend the growth phase of existing hairs. Used alongside finasteride, the combination tends to outperform either treatment alone.

For men on TRT who are concerned about hair loss, some prescribers will discuss adding low-dose finasteride to the regimen. This is a decision to make with your prescriber because finasteride's DHT-blocking action affects the whole body, and there are considerations around sexual side effects and fertility to work through.

If you're looking at hair loss treatments separately from TRT, Totiva's hair loss service offers pharmacist-led consultations for finasteride and minoxidil for men.

Should You Stop TRT If You Develop Acne or Hair Loss?#

Rarely, and not without speaking to your prescriber first.

For acne, the approach should almost always be to treat the skin rather than abandon the therapy. TRT is prescribed for a clinical reason, whether that's symptomatic hypogonadism, gender-affirming therapy, or another indication, and the benefits for most patients significantly outweigh a manageable skin side effect. Work through the treatment options above and give them adequate time.

For hair loss, if you have a strong genetic predisposition and the prospect of accelerated thinning is a significant concern, it's a conversation worth having before you start TRT rather than after. Your prescriber can help you weigh the benefits of testosterone therapy against the risk and discuss whether prophylactic finasteride makes sense in your situation.

If you're on NHS TRT and experiencing side effects, your GP or endocrinologist is the right first port of call. Private TRT clinics registered with the CQC in the UK are required to follow the same MHRA-regulated prescribing standards, so they should also have appropriate processes for managing side effects and adjusting treatment.

Testosterone Formulations and Side Effect Risk#

Not all testosterone preparations are equal when it comes to side effect profiles.

Gels tend to provide the most stable hormone levels day to day, which can translate to fewer side effect peaks. If you're noticing acne flares or increased shedding in the days following an injection, raising this with your prescriber is worthwhile. Switching formulation sometimes makes a meaningful difference.

Oestrogen, SHBG, and the Bigger Picture#

Testosterone doesn't act in isolation. Sex hormone-binding globulin (SHBG) is a protein that binds testosterone in the bloodstream, keeping it inactive. Only free (unbound) testosterone can be converted to DHT or act on androgen receptors. Men with lower SHBG levels have more free testosterone available, which can translate to higher DHT activity and potentially more pronounced skin and hair effects.

Testosterone is also converted to oestradiol (an oestrogen) by an enzyme called aromatase. Some TRT patients are prescribed aromatase inhibitors to manage this, though this is controversial and not universally recommended. The balance between androgens and oestrogens affects multiple body systems, and side effect management should always factor in the full hormonal picture rather than testosterone levels in isolation.

This is one reason why monitoring is important during TRT: a prescriber looking at the full picture, including free testosterone, SHBG, oestradiol, and DHT levels where appropriate, is better placed to adjust your treatment than someone managing symptoms alone.

A Practical Summary#

If you're on TRT and developing acne: start with benzoyl peroxide or adapalene, keep skin clean, avoid heavy moisturisers on affected areas, and speak to your GP if it's not improving within six to eight weeks of consistent treatment. Don't stop testosterone without talking to your prescriber.

If you're on TRT and losing hair: check your family history first. If male pattern baldness runs in your family, TRT may be accelerating a process that was already in motion. Finasteride and minoxidil are the evidence-based options, and the sooner you start, the better the likely outcome.

For men who haven't yet started TRT but are thinking about it, it's worth having these conversations upfront rather than navigating the side effects alone after the fact.

If you're exploring treatment for any related conditions, Totiva's pharmacist-led online consultations make it straightforward to get assessed by a UK clinician without a GP referral. You can start a hair loss consultation here.