The Unwinder is reader-supported, meaning we may earn an affiliate commission if you buy through a link from our site.


4 DL-Phenylalanine Reviews To Read Before You Buy

What is DL Phenylalanine?

Phenylalanine is an essential amino acid–one of the nine (out of twenty-one) amino acids that the human body cannot synthesize in sufficient quantities to meet its needs.

Like most chemicals, it comes in two isomers–two versions with identical chemical formulas, but different arrangements of atoms. The two stereoisomers of phenylalanine are called D-phenylalanine and L-phenylalanine, and each has ever so slightly different chemical properties. DL-phenylalanine, or DLPA, is simply a mix of both forms of the amino acid. 

Like all amino acids, phenylalanine serves a variety of functions in the body–in this case, most of the notable benefits of phenylalanine are brain-related.

DL Phenylalanine Benefits

In the brain, phenylalanine serves primarily as a precursor to other chemicals, most notably the amino acid tyrosine and the neurotransmitter phenethylamine.

Tyrosine is a direct precursor to L-dopa, which converts to dopamine, epinephrine (adrenaline), and norepinephrine. This means that it, and by extension phenylalanine, are needed for energy, pleasure and motivation.  

Phenethylamine is a neurotransmitter that is produced by the human brain during times of high stress or exertion, and exhibits amphetamine-like effects, including stimulating the synthesis of dopamine and adrenaline. Unlike amphetamine however, it has a half-life of only 15 minutes or so.  

A small amount of phenylalanine is stored in the brain to be used for synthesis of tyrosine and phenethylamine, as well as for protein synthesis. The brain’s phenylalanine stores can become depleted, and as you’ll see, this depletion has been implicated in brain disorders such as depression.  

Stimulant drugs which cause the brain to produce dopamine and adrenaline can also deplete the brain’s phenylalanine (and tyrosine) stores. Anecdotally, supplementation of DL-phenylalanine has been widely reported to reduce stimulant dependency and withdrawal symptoms, making it easier to quit caffeine.

Note that because tyrosine cannot be converted back into phenylalanine, supplementing tyrosine will not fix phenylalanine depletion, whereas supplementing phenylalanine improved levels of both amino acids. 

DL-Phenylalanine For Depression

Patients with depression often have low levels of phenylalanine and tyrosine in the brain, which impairs the brain’s ability to produce dopamine. This lack of dopamine leads to low energy and lack of motivation.  

Depression often involves DLPA depletion, which in turn causes deficiencies in neurotransmitters derived from DLPA, particularly dopamine.

Accordingly, one study found that supplementation of 200 mg of DL-phenylalanine per day was able to reduce depression in most patients; out of 20 study participants, 12 were able to be discharged (meaning they weren’t necessarily “cured” but no longer needed inpatient treatment) and another 4 showed some improvement, with the remaining 4 showing no response.  

200 mg a day is a very low dose too; most studies use doses of 500 mg or more, and most DL-phenylalanine supplements are dosed at at least 500 mg. It is likely, in fact, that a higher dosage would have produced better–or faster–results.  

DLPA For Opiate Withdrawal

DLPA is a vital component in the endogenous opioid/analgesia system. Pain may deplete phenylalanine much the same way depression or caffeine usage does, and DLPA supplementation can reduce opiate withdrawal symptoms by fueling the endogenous analgesia system. 

However, DLPA can also potentiate opioids when taken in combination with them. This could be useful for slowly weaning oneself off of opioids, but it could also lead to dangerous overdoses or increasing addiction if not combined with a lowered opioid dosage.

As such, DLPA should only be used by opioid users at the recommendation of a doctor, and must be used with care.  

DL Phenylalanine Dosage

DLPA is typically dosed at 500 to 1,000 mg, most often first thing in the morning. Either this dosage or a lower dosage can be repeated at noon, or taken as needed.  In any case, dosing should be limited to 2,000 mg a day, total.

DLPA will not have a very quick stimulatory effect since it has to be absorbed, and then processed into other neurotransmitters before becoming dopamine or adrenaline.

Our DL-Phenylalanine Reviews

Life Extension DL-Phenylalanine

Best DL-Phenylalanine Capsules

Life Extension DL-Phenylalanine

These 500 mg capsules are right in line with the dosage used in most studies as well as the majority of anecdotal success stories. They allow you to easily adjust your dosage and timing within the recommended range of 500 to 2,000 mg per day.

As for the manufacturer, Life Extension is one of the most trusted brands in the business, with a reputation for purity and quality built up over years. It follows industry best practices and regularly gets its products lab tested for purity.

Pure Encapsulations DL-Phenylalanine

Best High Dose DL-Phenylalanine Pills

Pure Encapsulations DL-Phenylalanine

If you know you’ll be taking 1,000 mg at a time, this product by Pure Encapsulations offers a modest cost savings and halves the number of capsules you have to swallow, at the expense of having less flexibility about dosing.  

Pure Encapsulations is less well-known than Life Extension, but it still follows supplement manufacturing best practices, and this product is hypoallergenic and GMO-free.

Bulk Supplements DL-Phenylalanine

Best Bulk DL-Phenylalanine Powder

Bulk Supplements DL-Phenylalanine

Simply put, this is the product to buy if you want powdered DLPA, and lots of it. Like, a six to twelve month supply of it.  

Bulk Supplements is the leading brand for high-volume powdered supplements. Never fancy but always affordable and reliable, all Bulk Supplements powders come in durable, re-sealable bags designed to be used for months after opening.

Best DL-Phenylalanine Tablets

Source Naturals DL-Phenylalanine Tablets

Each bottle of DL-Phenylalanine by Source Naturals contains 60 tablets, with each tablet providing 55 mg of calcium and 750 mg of DLPA.

It is recommended to take one tablet between 1 and 3 times daily.

Editor’s note: we are regularly updating this review. If you see any problems, weird interpretations of the data, or just want to say hi, please reach out to

Gradient in feature image by Gradienta on Unsplash

About the author

John Fawkes is the Managing Editor of The Unwinder. John is an NSCA-certified personal trainer and Precision Nutrition-certified nutritional counselor who has been featured on over two dozen websites and podcasts. He works with clients in Los Angeles and online, and can be reached on Instagram and Twitter.

Leave a Reply

Your email address will not be published. Required fields are marked *