Category Archives: Prolactin

ABS-201, Absci, Prolactin

Absci ABS-201: Targeting the Prolactin Receptor

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Absci ABS-201 Hair Growth
Absci ABS-201 and its hair growth compared to Minoxidil.

Absci (US) is an artificial intelligence (AI) drug and biologic creation company that is developing novel treatments via the use generative AI. One of the key products that they are focusing on is a prolactin receptor (PRLR) targeting injection based hair growth treatment called ABS-201. Phase 1 clinical trials for this product began in Australia at Sinclair Dermatology in December 2025.

Note that Hope Medicine (China)’s Phase 1 clinical trials for its competing prolactin receptor blocking HMI-115 injections also occurred at Sinclair Dermatology in 2022. Hope Medicine later completed Phase 2 trials in China in 2025. The company’s HMI-115 was licensed from Germany’s Bayer (whose patent was approved in 2019). So there is a lengthy history of research behind this concept of targeting the prolactin receptor to reverse hair loss.

The original version of this post is at the bottom. New updates are on top.

Update: June 24, 2026

Absci Raises $100 Million from Eli Lilly and others

After the below good news on Absci’s interim Phase 1 data for ABS-201, the publicly traded company raised $100 million via a common stock offering. The fundraising was led by Eli Lilly (US), the largest pharmaceutical company in the US. The funds will be used for both the hair loss and endometriosis programs. Subsequently, Absci’s stock rose by 36%.

Considering the early stage of Absci’s ABS-201 clinical trial progression, this is even more impressive than: Veradermics raising $150 million in Serie C Financing in 2025; and Pelage raising $120 million in Series B Financing in 2025. Both Pelage and Veradermics are currently in Phase 3 trials.

Update: June 24, 2026

Absci Announces Positive Interim Phase 1 Data

Absci just reported positive interim Phase 1 data from its first-in-human trial of ABS-201, an investigational anti-prolactin receptor (PRLR) antibody. The press release does not mention that this trial is taking place in Australia. The data comprises 32 healthy adult participants (with and without androgenetic alopecia) enrolled into four planned single ascending dose (SAD) cohorts. Dose levels evaluated were 150 mg, 450 mg, 900 mg and 1800 mg administered intravenously (IV).

Key points:

  • No serious adverse events were reported as of the data cutoff date.
  • The estimated half-life of at least 65 days means that ABS-201 would only need to be injected in patients 2-to-3 time over a 6-month period.
  • The first multiple ascending dose (MAD) of ABS-201 in a cohort of androgenetic alopecia participants has been initiated.
  • The interim proof-of-concept data is anticipated for the second half of 2026. Full proof-of-concept data is expected in early 2027.

Note that the full 227-person Phase 2 clinical trial is expected to be completed in July 2028.

Update: June 22, 2026

Joe Tillman (the Hair Transplant MentorTM) is interviewing Absci CEO Sean McClain today and the video will be released on Wednesday. If any reader has a question he/she would like to ask, please post it in the comments by 2pm PST today (Update: Interview video is now embedded below). Also, a recent article about Absci on seekingalpha is also worth a read.

Update: January 22, 2026

Absci is publishing numerous new videos on its YouTube channel. All of them are very encouraging so far.

Also check out the company’s detailed presentation on ABS-201 from the end of 2025.

Update: December 11, 2025

ABS-201 Regenerates Hair Stem Cells and Promotes Key Growth Modulators

Absci today unveiled new preclinical data for ABS-201. The data was generated using translational human ex vivo scalp models. It demonstrated that ABS-201 stimulates hair growth by regenerating the stem cell niche as well as by promoting additional key growth modulators. The studies were led by Dr. Ralf Paus, who says:

“Our study provides the first evidence that antagonizing prolactin signaling with ABS-201 could open a radically new chapter in future AGA management.”

Among the key findings:

  • ABS-201 significantly inhibits the PRLR signaling pathway.
  • ABS-201 prolongs the anagen phase by blocking catagen, and promoting hair matrix keratinocyte proliferation.
  • In addition, it increases the production of the hair growth-stimulatory growth factors IGF1 and FGF7.
  • ABS-201 protects and expands the hair follicle progenitor cell pool. It inhibits prolactin-induced apoptosis of K15+ stem cells , and increases their proliferation and capacity to generate CD34+ progeny. This is crucial, since the depletion of progenitor cells is a key hallmark of androgenetic alopecia.
  • It facilitates the reconversion of vellus hairs to terminal hairs.

Also of interest, long-time hair loss sufferer and former US soccer superstar Landon Donovan has teamed up with Absci. Way out of leftfield.

Update: December 4, 2025

Absci just announced that the first volunteers have been dosed in their Phase 1/2a HEADLINE study evaluating ABS-201. Absci will host a virtual KOL seminar on Thursday December 11 to discuss further details about this drug and its clinical trials.

Also check out this great detailed interview of Absci founder and CEO Sean McClain with ARK Invest’s legendary Cathie Wood.

Update: October 20, 2025

Absci to Begin Phase 1 Clinical Trials for ABS-201 in December 2025

In a new article about Absci’s ABS-201 hair growth injections that target the prolactin receptor, it is mentioned that Phase 1 clinical trials will begin in Australia in December 2025. The renowned Dr. Rodney Sinclair will oversee the trials at his Sinclair Dermatology clinic. Interestingly, Hope Medicine’s Phase 1 clinical trials for its prolactin receptor blocking HMI-115 injections also occurred in Australia at Sinclair Dermatology in 2022.

Of note, the Absci research team believes that ABS-201 could also cure premature greying by re-pigmenting the hair. This is based on their pre-clincial work on macaques, in which the animals’ hair reverted back from grey to black.

Key quote regarding Absci’s use of AI to develop this product:

“Using AI to develop the needle itself (in this case, the perfect antibody sequence) researchers were able to discover key antibody binding regions that could precisely target the prolactin receptor, thus ceasing hair loss. Using computer simulations, Absci was able to optimize certain drug qualities, including increased potency and decreased likelihood of negative immune response.”

Update: July 11, 2025

The CEO of Absci posted the below Tweet yesterday. The before and after macaque monkey image in there seems identical to the image from Hope Medicine’s HMI-115 and its effect on macaques. Strange. The same image can also be seen in their 2024 R&D document. Both HMI-115 and Absci’s ABS-201 target the prolactin receptor to regrow hair. Hope Medicine has already completed Phase 2 clinical trials, while Absci is yet to commence any human trials.

ABSCI Hair Growth Prolactin
ABSCI ABS-201 Hair Growth Prolactin.

April 6, 2025

Absci is a data-first artificial intelligence drug and biologic creation company that is unlocking novel treatments through the use generative AI. Most interestingly, one of the key products that they are focusing on is a hair growth treatment called ABS-201 that targets the prolactin receptor.

I first heard about the company in January 2025 when Absci received a $20 million investment from chip manufacturer Advanced Micro Devices (AMD). Unlike virtually all new entrants in the hair loss world, Absci has a great website. However, it should be noted that the company originally started operations way back in 2011, under the auspices of founder and CEO Sean McClain.

In March 2025, Absci presented on the subject of AI in dermatology at the Dermatology Innovation Forum. On a related note, in 2022, I wrote a post on AI and machine learning for hair loss drug discovery.

Absci Presentation on ABS-201

Considering that Absci’s pipeline page shows that ABS-201 is yet to even enter Phase 1 clinical trials, I was reluctant to write this post. However a new video presentation (embedded below) that the company uploaded in February 2025 changed my mind. It is titled “Absci R&D Day 2024”. The portion devoted to ABS-201 and hair loss starts at 1:19:40 and lasts for over an hour.

Also check out the company’s case study page on ANS-201. Interestingly, in the notes to the key mechanism of action diagram, they mention that ABS-201 also has the potential to restore hair pigmentation.

Absci currently has over 77,000 square feet of space between:

  • A state-of-the-art wet lab in Vancouver WA (US).
  • An advanced AI research lab in New York City (US).
  • A drug innovation center in Zug (Switzerland).

The company plans to begin Phase 1 clinical trials for ABS-201 in the first half of 2026. Their preclinical model demonstrated improved hair regrowth in comparison to minoxidil.

Absci ABS-201 versus Hope Medicine HMI-115

ABSCI ABS-201 Prolactin
ABSCI ABS-201 artificial intelligence developed prolactin receptor antibody for hair loss. Comparison to Hope Medicine’s HMI-115. Source: Absci.

Note that Absci’s AI-developed ABS-201 is similar to Hope Medicine’s HMI-115 that is currently in Phase 2 trials. The latter prolactin receptor antibody treatment for male and female pattern hair loss was originally developed by Bayer (Germany) who received a patent for it in January 2019. A few months later, Hope Medicine announced a global licensing agreement with Bayer to advance the development of this monoclonal antibody to target the prolactin receptor.

In the above screenshot from Absci’s R&D Day 2024 presentation video, they elaborate on some of the key differences between ABS-201 and HMI-115.

Ulo Personalized Hair Treatments

Clinical Trials, Prolactin, Rodney Sinclair

Get Paid $20,000 to Participate in a Hair Loss Clinical Trial

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Hair Loss Clinical Trial
Participating in a hair loss clinical trial in Australia could earn you AUD 27,460 (USD 19,500).

I have covered the renowned Sinclair Dermatology (Australia) that is run by Dr. Rodney Sinclair many times on this blog. They have conducted a number of hair loss related clinical trials in recent years. Their most important ones involved:

  1. HMI-115 from Hope Medicine (China) = blocking the prolactin receptor via injections. Phase 1 trials ended in 2022. Phase 2 trials were then done in China and finished in 2025.
  2. ABS-201 from Absci (US) = blocking the prolactin receptor via injections. Unlike HMI-115, this product is developed using artificial intelligence (AI). Phase 1 trials were supposed to have started in December 2025.
  3. Sublingual Minoxidil and Oral Minoxidil.

Dr. Sinclair is also one of the earliest researchers in regards to the destruction of the arrector pili muscle and its role in hair loss. His clinic is also conducting trials for US-based Dermaliq Therapeutics‘ prostaglandin F2α analogue hair growth product DLQ01 (thought to contain latanoprost).

A Hair Loss Clinical Trial that Pays $20,000

And you may even regrow some hair and reverse some grey hair as a bonus.

Earlier today, Australian media released a new video where it was mentioned that balding men could earn Australian Dollars (AUD) $27,460 to participate in a new hair loss related clinical trial. This amount is equal to US Dollars (USD) $19,500 at prevailing exchange rates. As a bonus, these injections may also stop and possibly reverse grey hair.

Per the video, the trial entails injections to block the prolactin hormone (and therefore prevent the prolactin receptor from causing baldness). However, the official government clinical trial page says the following:

“Approximately 4-6 Single Ascending Dose (SAD) IV doses will be tested and if safe and well tolerated, approximately 3-4 Sub-cutaneous Multiple Ascending Dose (MAD) doses will be tested in participants.”

The “subcutaneous” above means injections and the “IV” stands for intravenous. I think that you should expect both IV and injection delivery.

The above official government clinical trial page also states that the drug being tested is ABS-201 (which I mentioned earlier). It is both a Phase 1 and Phase 2 trial, with a 227 person enrollment target.

I would be wary of side effects if I was participating in this trial for an AI developed drug (unless you get the placebo). However, it should be noted that people who received the somewhat similar HMI-115 prolactin receptor blocker injections at Sinclair Dermatology in 2022 did not get serious side effects as far as I know.

Trial Details

The trial will be run by Sinclair Dermatology and Nucleus Network (both in Melbourne, Australia). On the latter’s website, they call it the Headline Trial, A separate trial participation link calls it the HAIR Trial. On the HAIR Trial page, it mentions the amount to be reimbursed as “up to $21,860” (AUD) for those eligible. This amount is lower than announced in the earlier embedded video. However, on the Headline Trial page there is a clearer elaboration about two options for participation (and hence the payment variation):

Option 1:

  • 4 sets of 3 overnight stays (12 nights total).
  • At least 20 follow-up visits.
  • Up to $27,460 (AUD) reimbursement for your time and commitment.

Option 2:

  • 4 dosing visits.
  • At least 18 follow-up visits.
  • Up to $21,860 (AUD) reimbursement for your time and commitment.

​​On the HAIR trial page, it says that the participants will receive 4 doses of the study medication over the first 6 months​. The total study duration is approximately 18 months and participants will be regularly monitored. Each clinic visit in Melbourne will take 1 to 2 hours. However, on Sinclair Dermatology’s website, it says:

“Patients will be asked to visit the clinic about 27 times over 18 months. There will only be 4 dosing visits.”

As far as eligibility goes, most of us will fail the first one in the below list. I am also not sure if they will accept non-Australian residents.

  • You “may” not be eligible if you have: used minoxidil, finasteride or anabolic steroids in the last 6 months; used dutasteride in the last 12 months; have previously had a hair transplant or scalp micropigmentation; are on prescription medications; or have certain heart, kidney, or liver-related health conditions,
  • You must be a man aged 18-65 years. However, in both the HAIR Trial and Headline Trial links, they also have an option for women to register their interest. Confusing.
  • You must weigh over 60 kgs (132 lbs).
  • You must have a balding spot on the top of their head (i.e., crown hair loss).

There are also other exclusion criteria in the official government clinical trial page.