This is a randomized, double-blind, placebo- and active-controlled parallel-group multi-center phase III study to evaluate the efficacy and safety of Rcombinant botulinum neurotoxin type A for injection (YY001)) in the treatment of moderate to severe glabellar lines.

Inclusion Criteria:

1. Male or female 18 to 65 years (inclusive) at the time of signing the informed consent form.
2. At screening and baseline, moderate to severe glabellar lines (grade of 2 or 3 on the 4-point Scale) at maximal frown as assessed by both the Investigator and the participant on-site.
3. Agree to participate in the study and sign the informed consent form.
4. At the discretion of the investigator, the participants can comply with the protocol requirements.
5. Females and/or males of childbearing potential and their partners: those who should be using effective contraception and have no plans for childbearing, egg donation (females), or sperm donation (males) from the signing of the informed consent form to 3 months after the last administration. Female participants of childbearing potential must have had a negative blood pregnancy test (human chorionic gonadotropin) within 7 days prior to the administration of study drug or a urine pregnancy test examination must be negative 3 days prior to the administration of study drug.

Note:

1. Women of childbearing potential are those who have experienced menarche, have not undergone sterilization (hysterectomy or bilateral salpingo-oophorectomy or bilateral tubal ligation), and are not in a state of post-menopausal (defined as absence of menstrual bleeding for 12 months prior to screening, without any other medical reason).
2. Effective contraceptives include: vasectomy, abstinence, intrauterine devices, hormones [oral, patch, ring, injections, implants], barrier methods [diaphragm, cervical cap, sponge, condom.

Exclusion Criteria:

1. Known allergy to any component of the test product (includes investigational product and comparator product), or hypersensitivity.
2. Previous cosmetic manipulation of the area between the eyebrows, within 12 months prior to screening; implantation of autologous fat or any permanent material; history of upper face lifting or semi-permanent prosthetic fillers, etc.; or plan to undergo upper face cosmetic manipulation during the study period (note: except for study drug injections);
3. Use of any botulinum toxin within 6 months prior to baseline, or planned use of botulinum toxin during the study (note: except for use of investigational drugs at the study site).
4. Use of nonsteroidal anti-inflammatory drugs including aspirin or anticoagulants (e.g., heparin, coumarins, non-vitamin K antagonists, oral anticoagulants within 1 week prior to baseline.
5. Use of medications that affect neuromuscular transmission within 4 weeks prior to baseline, including but not limited to: muscarinic agents, aminoglycosides, anticholinergic agents, benzodiazepines.
6. At screening and baseline, skin abnormalities at the injection site
7. Inability to substantially lessen glabellar lines by physically spreading them apart, as determined by the investigator.
8. Ptosis, significant facial asymmetry, excessive skin laxity at screening or baseline, or a history of any of the above.
9. A history of facial nerve palsy.
10. History or presence of such diseases that interfere with neuromuscular function, including, but not limited to: myasthenia gravis, Lambert-Eaton syndrome, amyotrophic lateral sclerosis; diseases or a history of such diseases that can cause localized neuromuscular function, including, but not limited to: swallowing/breathing difficulties, diplopia, angle-closure glaucoma, significant drooping of the eyes and eyebrows, or flaccidity of the skin/excessive weakness or weakness of the corrugate and/or procerus;
11. Have other concomitant diseases, including but not limited to cardiovascular, respiratory, gastrointestinal, endocrine, and other systemic diseases, malignant tumors, and immunodeficiencies, which are assessed by the investigator to be unsuitable for participation in clinical research.
12. History of drug or alcohol abuse.
13. History or presence of epilepsy.
14. Female who is pregnant or breast feeding.](streamdown:incomplete-link)

Double-blinded