Letrozole Background and History

Letrozole first burst onto the market in 1997 when it was granted approval from the FDA and marketed by Novartis under the name of Femara.

Despite this, the drug is more commonly referred to by its generic name of letrozole.

But is letrozole a steroid? The short answer is no, but it is commonly associated with anabolic steroid use.

This compound belongs to a type of drugs known as aromatase inhibitors, all of which have the ability to dramatically reduce the effects that estrogen has on the body. Letrozole was originally developed to treat breast cancer in post-menopausal women but the bodybuilding community quickly identified off-label uses too.

Due to its powerful anti-estrogenic effect, letrozole became sought after by bodybuilders who were taking anabolic steroids. This is because although bodybuilders seek to increase their testosterone levels with anabolic steroids, this causes an interaction with the aromatase enzyme which in turn pushes up the levels of estrogen in the body.

As an AI, letrozole works in a very different way to Nolvadex, another type of anti-estrogenic drug known as a SERM. Nolvadex only blocks the estrogen receptor without affecting the levels circulating in the body. Letrozole has a far more powerful action, not only actively lowering the amount of estrogen circulating by inhibiting its release but simultaneously increasing the production of testosterone too.

For any anabolic steroid user who is experiencing estrogenic side effects, this lowering of estrogen levels can be very useful.

Stacking info

Letrozole isn’t a drug which is generally used on its own because its ability to increase testosterone production is modest.

Instead, a letrozole stack typically includes at least one – if not more – anabolic steroids which could have an estrogenic effect. Not all anabolic steroids produce the same results and some interact directly with the aromatase enzyme. In these circumstances, letrozole can be very useful to take as a precautionary measure to stop unwanted effects developing.

picture of letrozole chemical structure

Letrozole can also be added during a cycle if there are any estrogenic effects which have developed, such as water retention or gyno.

How it is administered

You will be able to find Letrozole pills but these are usually only obtained with a prescription. If you buy letrozole online, you may be able to find tablets from alternative sources.

However, it’s much more common to purchase Letrozole as a liquid. This is sold as a research chemical so is far more widely available.

Dosage info

The Letrozole dosage depends on whether you’re planning on using the drug as a preventative measure or because you’ve noticed the start of estrogenic side effects.

If you’re purely being cautious, then it’s usually possible to take a much more conservative dose of the drug. If, however you’ve noticed the early signs of gyno, then you’ll need to be much more aggressive with your dosage.

The typical dosage range starts at 0.25mg and increases up to 1mg, taken every other day.

The tablets normally come in a standard dose of 2.5mg but this will almost certainly be too strong for regular use. The only potential exception is for treating gynecomastia where 7-14 days at 2.5mg may just blast away any early signs.

Half life info

The half life of Letrozole is two days which means that it won’t disappear from the system quickly and you’ll only have to dose every other day to maintain peak serum levels.

Positive effects

For bodybuilders, letrozole will help to strip out the unwanted estrogenic effects and provide a much leaner and more ripped appearance. Estrogen can sometimes cause water retention and a much softer, puffier appearance. Letrozole can get rid of any excess water, creating a much leaner, hardcore look to the muscles.

In some cases, the water retention can be so problematic that it can increase the overall blood pressure. This could lead to other cardiovascular problems developing if not brought back under control.

Gynecomastia is possibly one of the primary concerns for bodybuilders taking anabolic steroids and can ruin a lean, hard appearance. Once established surgery can be the only solution to reverse the effects. Gyno is caused by an excess of estrogen but letrozole is so powerful it can completely banish gyno, even after it has started to develop.

Potential side effects

Letrozole is a very powerful drug and although it can be invaluable in reducing the androgenic effects of anabolic steroids, it can carry some unpleasant side effects of its own.

In general, Letrozole side effects can include weakness and fatigue but if the individual is taking anabolic steroids, this is unlikely to be the case. The only time it’s likely to become a problem for bodybuilders is during a pre-competition harsh cutting cycle, where training is intense and calorific intake is low.

The other symptoms you might experience include hot flashes, headaches, pain in the joints, raised blood pressure and depression.

Bone mineral density can also be reduced by Letrozole but once again, this effect should be counteracted by the increase in bone density which is often the result of anabolic steroid use.

One side effect of Letrozole that remains a concern however is the potential effect on cholesterol. Studies have shown that HDL can be reduced by Letrozole particularly when combined with an anabolic steroid, with the effect not being simply additive but accumulative. When these two types of drugs are taken together HDL cholesterol can drop by as much as 20%.

Therefore, a healthy lifestyle is essential, with particular attention to eating a clean diet and including cardiovascular exercise in your training regime. Some individuals find adding an antioxidant into a Letrozole stack is helpful.

Estrogen can play a part in keeping the skin and hair healthy but although the drug will decrease estrogen levels, letrozole and hair loss are not usually connected.


This drug is currently banned in India because one study showed a link to birth defects in babies. However, a Canadian study was unable to replicate the results and in the rest of the world, Letrozole remains licensed for use.

Because of the known effect on cholesterol, anyone with a history of raised cholesterol or cardiovascular disease should avoid Letrozole. A SERM could be substituted in its place; it’s not quite as effective in managing estrogenic effects but in many cases it is sufficient.

Is it safe for women to use?

Although some female bodybuilders may want to reduce their overall fat levels, tinkering with estrogen is much more of a problem.

Estrogen is essential to the female body and many of its functions and an AI can drop levels too low, particularly one so powerful as Letrozole.

For this reason, Letrozole is not recommended for any women of child-bearing age, and only to be used cautiously in others.  This is because there is an interaction between letrozole and fertility.

Will PCT be required?

Letrozole helps to promote natural production of testosterone so when taken on its own, there’s no negative effect on the body’s own testosterone. The problem arises because Letrozole is typically taken alongside another drug which will suppress the production of testosterone.

Therefore, while PCT isn’t necessarily to counteract the effects of Letrozole by itself, PCT will be required in order to support the return to natural production of testosterone because of the effects of the other drugs taken.

Letrozole can help to stimulate the body to produce testosterone but it’s not sufficient to take in isolation as PCT; this is because of the suppressing action on the estrogen levels in the body. PCT is supposed to bring the body back to natural levels of hormones so suppressing estrogen will impair this end goal.

Typical cost

The one official brand of Letrozole is Femara which is sold in blister strips, each containing 10 2.5mg tablets. It is possible to buy generic brand Letrozole and compared with other drugs, there’s a much lower incidence of counterfeits and fakes.

There are two different grades of letrozole for sale available: pharmaceutical and research.

Femara is a pharmaceutical grade product; some of the generic brands may also be pharmaceutical grade but that can be said with far less certainty. To buy letrozole at a pharmaceutical grade, you can expect to pay $8-10 per 2.5mg tablet. If you buy from a supplier who specifies a minimum quantity for each order, you can buy letrozole from $2-4 per tablet. Minimum limits are often set at a price of between $200-400.

Research grade letrozole typically comes in liquid form where a 30ml bottle contains 2.5mg per ml. This can then be administered either via a dropper, a syringe or a measured spray pump. You can expect to pay approximately $50 per bottle.

Legality of purchase and its usage in the US

In the US, although the FDA has granted approval for use in humans Letrozole remains a prescription drug. This means that a physician may only prescribe it if there is a legitimate medical cause. It may not be prescribed for recreational purposes such as bodybuilding.

Therefore, to acquire Letrozole in the US to use alongside anabolic steroids means resorting to illegal means. However, because it’s not classified as a controlled substance, there’s no harsh penalties for either use or distribution, despite the fact it cannot be readily purchased over the counter.

There is however one loophole in the law to be aware of: the ability to purchase it as a research chemical. This makes it much easier to source and purchase in liquid form.