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        <issuerCik>0001576885</issuerCik>
        <issuerName>Acumen Pharmaceuticals, Inc.</issuerName>
        <secFileNumber>001-40551</secFileNumber>
        <issuerAddress>
          <com:street1>427 PARK ST.</com:street1>
          <com:city>CHARLOTTESVILLE</com:city>
          <com:stateOrCountry>VA</com:stateOrCountry>
          <com:zipCode>22902</com:zipCode>
        </issuerAddress>
        <issuerContactPhone>925-368-8508</issuerContactPhone>
        <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>Siemers Eric</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
        <relationshipsToIssuer>
          <relationshipToIssuer>Officer</relationshipToIssuer>
        </relationshipsToIssuer>
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      <securitiesInformation>
        <securitiesClassTitle>Common Stock</securitiesClassTitle>
        <brokerOrMarketmakerDetails>
          <name>Merrill Lynch</name>
          <address>
            <com:street1>225 Liberty St</com:street1>
            <com:street2>Floor 37</com:street2>
            <com:city>New York</com:city>
            <com:stateOrCountry>NY</com:stateOrCountry>
            <com:zipCode>10281</com:zipCode>
          </address>
        </brokerOrMarketmakerDetails>
        <noOfUnitsSold>3124</noOfUnitsSold>
        <aggregateMarketValue>11603.78</aggregateMarketValue>
        <noOfUnitsOutstanding>57910461</noOfUnitsOutstanding>
        <approxSaleDate>01/18/2024</approxSaleDate>
        <securitiesExchangeName>NASDAQ</securitiesExchangeName>
      </securitiesInformation>
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        <securitiesClassTitle>Common Stock</securitiesClassTitle>
        <acquiredDate>01/17/2024</acquiredDate>
        <natureOfAcquisitionTransaction>Vesting of restricted stock unit award</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Acumen Pharmaceuticals, Inc.</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>3124</amountOfSecuritiesAcquired>
        <paymentDate>01/17/2024</paymentDate>
        <natureOfPayment>Granted as part of issuer equity compensation plan</natureOfPayment>
      </securitiesToBeSold>
      <nothingToReportFlagOnSecuritiesSoldInPast3Months>Y</nothingToReportFlagOnSecuritiesSoldInPast3Months>
      <noticeSignature>
        <noticeDate>01/18/2024</noticeDate>
        <planAdoptionDates>
          <planAdoptionDate>09/15/2023</planAdoptionDate>
        </planAdoptionDates>
        <signature>Eric Siemers</signature>
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text: 144
  0001866239
  XXXXXXXX
  LIVE
  0001576885
  Acumen Pharmaceuticals, Inc.
  001-40551
  427 PARK ST.
  CHARLOTTESVILLE
  VA
  22902
  925-368-8508
  Siemers Eric
  Officer
  Common Stock
  Merrill Lynch
  225 Liberty St
  Floor 37
  New York
  NY
  10281
  3124
  11603.78
  57910461
  01/18/2024
  NASDAQ
  Common Stock
  01/17/2024
  Vesting of restricted stock unit award
  Acumen Pharmaceuticals, Inc.
  N
  3124
  01/17/2024
  Granted as part of issuer equity compensation plan
  Y
  01/18/2024
  09/15/2023
  Eric Siemers